Electrical connector



Jan. 6, 1942. R. R. Ma cDONALD 2,269,314 ELECTRICAL CONNECTOR Filed May 23, 1941 A C I 3 666-1 10 12 $3 38 IQ.

E El 6 6 40 I l I L1-" :3 61 EEOY TLeIZ' m Patented Jan. 6, 1942 I UNETED STATES PAfI'EI IT- OFFICE g 2,269,314 v ELECTRICAL Cameron 2 kob floyltiacdonalm liayside, N. Y. Application. May 23, 1941, Serial Mlasmss 3 Claims, (01. 173-332) This invention relates to electrical connectors,

or switches, of the type wherein two body memments are releasably held in operative relationship.. A form of connector of this-type is disclosed in United States Patent No. 1,956,037,- dated April 24, 1934. v a V I An object of the invention is-to improve the construction of the prior connector in order to reduce the cost of manufacture thereof, to ensure a more flexible and efiective electrical contact between the complementary terminal elements than formerly, and to facilitate the engagement and disengagement of said as occasion may require. I v 5 Another object of the invention is to reduce to a minimum the liability of destructive arcing contact of the opposing elements during their association and separation, thus prolonging the effective life of the connector, or switch, when it is subjected to repeated circuit interruptions.

With these and other objects in view my invenelements tion comprises features of novelty which will be closed conof the Fig. 4 is a sectional detailof the telescoping ends of the plug and socket elements, showingthe clamping sleeve in initial abutting relation to the resilient members of the socket- Fig. 5 is a sectional detail of one of the blocks vofthe connector showinglocking means for'the confined end of the terminal bar; as.on the'line 1 5-5 of Fig. 3. v

Referring to the drawing, 10 and; I I rdesignate complementary terminal bars of conducting material, preferably cylindrical in cross-section,

which bars are fixedly held inthebores-lZiand I3 of two bodies or blocks l4 and |5, respectively,

of. insulating material. These blocksare suitably recessed, .at their outer ends, as at lfi,:for the passage of the leads I! of a powerline and the current carrying leads l8to'the bars. H andI-lll, respectively. .The leads'are electrically'connect ed to theterminal bars as hereinafterdescribed.

vEach of the terminal bars 50 is circumferentially. reduced to form a plug l9 which extends beyond the inner end of the block 14 and terminates in a substantially semi-spherical head portion 20, constituting a male contact member; and each of the bars I I is circumferentially reduced (as at 2|), longitudinally bores.(as at 22) and slotted (as at 23) toprovide a female member. having resilient members 24 0f less diameter than the bore I 3 and preferably terminating inwardly of theadjacent end of the block l5. The normal diameter of the bore ofthe socket elementis equal-to. that of the head 20, or substantially so, in orderto permit the-free telescopic entry of the headinto the socket element until the as-' sociated blocks Hand I5 have been relatively moved into close contactone with the other, as will presentlyappear.

The reducedportion 2 lof the bar 2 ll is short of the free extremityof the bar, thus presenting a furcated circumferential contact portion 25. This portion issuitably-bevelled at its outer end, thusproviding a divided cam face 25. That portionof the bore in the block l5 surrounding the contact-portion 25,-is enlarged, as at .21; to afford a recess for the free entry thereinto of theme-- jecting portion 28-ofa sleeve 29 which is afiixed to andforms in effectan integral part of the terminal bar Ill. .The internal diameter of'the projecting portion-of the sleeve is slightly less thanthe external diameter of the opposing contact portions25 of-the socket members 24, the extremity of the sleeve being bevelled to present a-cam' surface'30- which, immediately preceding the complete entry of the plug in the socket 'element,--impinges against the annular cam surface 26 presented by the resilient members of the socket element, as seen in Fig. 4.

The angularity of the cam surface 30 on the sleeve is less than that of the divided cam surface 26 of the socket element, so that in the closing ofthe electric circuit bythe connector the sleeve-cam initially bears against the outer edge 3I- of the-socket cam 26,- thus bowing the socket members radially'inward and in intimate 'contact with the body of the plug and the sleeve,-

which spaced contact is maintained throughout the locking movement, thus ensuring the clasticity of the members between their free ends and the fulcrum head. Consequently the members are uniformly and positively moved in con-' tact with the inner surface of the sleeve without jamming such members between the sleeve and the shank of the plug; it being noted that when, by virtue of such non-jamming condition during the closing force on the blocks, the sleeve overcomes and initially overlaps the opposing ends of the resilient members, said blocks are abruptly moved into close end to end contact. In the resulting absence of extended metal to metal contact areas, all liability of arcing contact between the telescopic elements during their engagement or disengagement, is reduced to a minimum. Moreover, in the event of the internal burning of the extremities of one or more of the resilient members of the socket element, on account of repeated interruptions of the electric circuit, such members, owing to the clearance between them and the shank of the plug, will be forced by the sleeve 29 in intimate electrical contact with the head of the plug, and this without jamming of the elements. It will also be seen that the forcible bowing of the female members under opposing pressure against the exterior edge and the interior wall of the plug head and the sleeve 29, respectively, not only insures efiicient electrical contact at the respective points of contact, but also holds the bodies or blocks firmly yet detachably in close relation without the use of external locking devices.

The hereinbefore described construction and co-operative relation of the terminal elements, by virtue of the resulting flexibility of the assembly, permits greater tolerance in the dimensions of the connector than formerly, thus materially reducing the manufacturing cost.

As a simple and efficient means to lock the terminal bars l0 and H in their respective blocks, and to prevent the accidental withdrawal of the bars, the inner end portion of each of the bars is reduced transversely, as at 33, to form a recess in communication with a vertical bore 34 inthe block, the floor of the recess being bored and tapped, as at 35, for the reception of the terminal screw 36 for the lead. Before the entrance of the screw a suitable washer 31 is driven tightly into the recess, which washer in conjunction with the opposing wall of the bore 34, thus effectually prevents the accidental withdrawal of the bar until the screw and washer are removed, and also provides an increased contact area for the lead. The mouth of the vertical bore 34 is closed by a reinforcing plate 38 which is fixedly held by screws 39 in a transverse recess in the top of the block, suitable insulation 40 being interposed between the block and the plate.

'having at its outer or free end a cam surface to co-act with the opposing ends of said resilient members and thereby force said external projections toward yet free from the said shank and in electrical contact with the inner surface of the annular member, the bodies of the said resilient members by the resulting bowing thereof being pressed hard against the said head in opposition to the resistance of the external projections of said resilient members by the inner wall of said annular member.

2. A connector embodying terminal members having telescopic male and female elements, the male element comprising a shank having a head at the free end thereof of greater diameter than the shank, and the female element comprising longitudinally-extending resilient members having an internal diameter substantially equal to the maximum diameter of said head, said resilient members having at their free ends external projections, and being beveled to provide a divided cam surface, and a projecting annular member mounted with the male element adapted to receive the free ends of the resilient members and having its outer or free end beveled to provide a cam surface of different angularity from that of the first-named cam surface so as to present a small contact area between the two cam surfaces and thereby co-act to force said external projections toward yet free from the said shank and in electrical contact with the inner surface of the annular member, the bodies of the said resilient members by the resulting bowing thereof being pressed hard against the said head in opposition to the resistance of the external projections of said resilient members by the inner wall of said annular member.

3. A connector embodying terminal members having telescopic male and female elements, the male element comprising a shank having a head at the free end thereof of greater diameter than the shank, and the female'element comprising longitudinally-extending resilient members having an internal diameter substantially equal to the maximum diameter of said head, said resilient members having at their free ends external projections, and a projecting annular member mounted with the male element adapted to receive the free ends of the resilient members, and cam means adapted to press the free ends of the resilient members toward each other as they enter the annular projecting member to force the free ends of the resilient members over the head and yet free of the shank of the male element, the bodies of said resilient members by the resulting bowing thereof being pressed hard against the said head in opposition to the resistance of the external projections of said resilient .members by the inner wall of said annular member.

RO-B ROY MACDONALD. 

